1. NHS - HUMAN ANATOMY/PHYSIOLOGY Dr. Smith CHAPTER 6
MUSCULAR SYSTEM
NHS - HUMAN ANATOMY/PHYSIOLOGY
Dr. Smith
CHAPTER 6

2. MUSCLES 600+ organs ONLY CONTRACT - GET SHORTER
Muscular System made up of Skeletal, cardiac, Smooth
Striated Muscle Tissue: has cross strips or striations - skeletal and cardiac
Non - Striated: NO bands: IN - Voluntary
Cardiac - involuntary striations

3. Types of Muscle Tissue Striated
Skeletal - - responsible for moving bones - voluntary
Cardiac - bulk of heart, has interclated disks - keeps muscle in contact - involuntary
NON-STRIATED
Smooth - involuntary, blood vessel walls, digestive system

5. Each muscle served by one artery, one nerve, and one or more veins
Enter/exit near central part and branch through connective tissue sheaths
Every skeletal muscle fiber supplied by nerve ending that controls its activity
Huge nutrient and oxygen need; generates large amount of waste

7. STRUCTURE OF SKELETAL MUSCLE
Origin - muscle attachment to bone - no movement
Insertion - muscle attachment to moveable (joint)
Tendons - anchor muscle to bone - great strength/flexibility
Bursae and synovial membranes

9. Muscle Microscopy Muscle fibers - muscle contractile cell
Composed of thick and thin myofilaments
Made of proteins
Actin - thin filaments
Myosin - thick filaments

10. SACROMERE (CONTRACTLIE UNIT)
Area from Z line to Z line

12. Sliding Filament Model
Muscles contract by thin myofilament moving toward thick myofilament
“Bridges” formed between the myofilaments pull the sarcomeres closer
Requires ATP and Ca

13. Major events in muscle contraction/relaxation

14. Energy Sources for Contraction
ATP molecules supply energy
Creatine Phosphate make possible the formation of ATP from ADP
Creatine phosphokinase makes creatine phosophate and stores additional energy

15. Oxygen role in muscle contraction
Hemoglobin - molecule that oxygen binds to in RBC
Myoglobin - molecule that oxygen “loosely” binds to in muscle - makes them red

17. Functions of Skeletal Muscle
Movement - muscle’s insertion bone moves toward the origin
prime mover - main muscle responsible for movement
synergist - helper muscles
antagonist - produces opposite movement

18. FUNCTIONS OF MUSCULAR SYSTEM
Muscle tone maintains posture
Tonic contraction - does not move body parts - keeps posture - opposite of gravity
POSTURE
Hypothermia - decrease in body temperature
Hyperthermia - increase in body temperature
HEAT PRODUCTION

19. MUSCLE FATIGUE THE DECREASING STRENGTH OF MUSCLE CONTRACTION
OXYEGN DEBT INCREASES FATIGUE
Lack of ACH, and lactic acid build up support fatigue
AEROBIC VS. ANAEROBIC RESPIRATION

20. NERVOUS SYSTEM AND MUSCLES
NERVOUS SYSTEM - IMPORTANT ROLE IN MUSCLE CONTRACTOIN - PARLYSIS - MULTIPLE SCLEROISIS
Muscle cells - stimulated by motor neurons
Chemicals released at neuromuscular junction

21. Stimuli
Threshold stimulus - minimum level of stimulation required for contraction.
“All or nothing” - Once a muscle’s threshold is reached all the muscle fibers contracts all the way
Recruitment - the amount of fibers involved in contraction - the more fibers the more strength

22. Types of Contraction Twitch - quick, jerky response to stimuli
tetanic - sustained and steady contraction (tetanus
isotonic - muscle shortens - insertion moves toward origin
isometric - the same distance - tone of muscle increases - - repeated isometric makes muscles larger and stronger

23. Exercise on Skeletal Muscle
During inactivity, muscles shrink in mass - disuse atrophy
Exercise causes increase in muscle size - hypertrophy
Strength training - heavy resistance - increases myofilaments in muscle fiber
endurance training (aerobic) - increases # of blood vessels to/in muscles, increases mitochondria

25. MUSCLES - FACIAL

27. Movements of Muscles
Flexion - movement that makes angle between bones smaller
Extension - movement that makes angle between bone larger
Abduction - moving away from midline
Adduction - moving toward the midline
Rotation - movement around axis
Supination/Pronation - Movement to face up/ face down
Dorsiflexion/Plantary Flexion